1. Field of the Invention
The present invention relates to substrate cleaning apparatuses and, more specifically to a cleaning apparatus adapted to efficiently and stably provide automatic removal of foreign matters adhering to the surface of a liquid crystal panel, such as cullets and sealing resin.
2. Description of the Background Art
In manufacturing a liquid crystal panel, two glass plates are bonded, the bonded glass plates are cut to have a prescribed size, a liquid crystal is transferred between the bonded and cut glass plates, and deflection plates are bonded on both surfaces of the bonded glass plates.
In the process of manufacturing a liquid crystal panel, when cutting the bonded glass plates to have a prescribed size, cullets (powder or small fragments of glass) produced by the cutting step may stick (in a solid state) to the surface of the glass plate, or a sealant may stick to the glass surface around a sealant transferring portion when sealing the sealant transferring portion after the liquid crystal is transferred between two glass plates.
Because of such foreign matters, i.e., cullets and sealing resin, sticking to the surface of the glass plates in the manufacturing process of the liquid crystal panel, the next step of bonding deflection plates would not be properly performed. Thus, these foreign matters have to be removed.
In a conventional method of removing the above mentioned foreign matters, a liquid crystal panel placed in water is set on a cleaning stage that is sprinkled with water, and a cleaning tool provided with a polishing sheet is soaked with water. The cleaning tool is manually held for manual polishing of the liquid crystal panel set on the cleaning stage.
After the cleaning step, the liquid crystal panel is passed through a brush rotating in a cleaning tank that is sprinkled with water by a cleaning apparatus. In this way, dusts, water scale and so on that are relatively weakly adhering to the surface of the liquid crystal panel are removed. Thereafter, the liquid crystal panel is dried out after being passed through an air knife.
After the liquid crystal panel is passed through the cleaning apparatus, the surface thereof is visually inspected, and remaining foreign matters are removed by a cutter or a cloth soaked with a solvent.
Methods of removing foreign matters on the panel surface include a cutter blade rotation method and sheet-rotation polishing method, in addition to manual cleaning.
In the cutter blade rotation method, at least two blades are provided, which are subjected to rotation and revolution and brought into contact with the liquid crystal panel so as to scrape off the foreign matters.
In the sheet-rotation polishing method, a stage provided with a sheet is rotated, and an object to be cleaned is brought into contact with the stage from above, for polishing on the rotating stage.
The feeding and rotation of a polishing tape allow the object to be constantly kept in contact with a new portion of polishing tape.
However, the above described conventional methods of cleaning the liquid crystal panel, including manual cleaning, cutter rotation method and sheet rotation method, suffer from the following problems.
The manual cleaning is accompanied by a considerable variation in workability and considerable loss time. In addition, as liquid crystal panels increase in size, instability in removing foreign matters become conspicuous and a loss time increases.
In the cutter rotation method, scratches are likely to be caused over the surface of the object. In addition, there is a variation in cleaning capability depending on a precision associated with, e.g., surface undulation of the object and the like, whereby a stable removing effect cannot be produced.
In the sheet-rotation polishing method, the size of an object is limited. Thus, it is difficult to increase the size of the object, and a sheet consumption is extremely high. In addition, pressure control is difficult during polishing, polishing unevenness is likely to be caused, and foreign matters adhering to the sheet may cause scratches.
One object of the present invention is to provide a substrate cleaning apparatus capable of enhancing operation efficiency with reduced operation time for removal of foreign matters, stably removing foreign matters, providing a high-quality substrate without causing a problem of foreign matters, and cleaning a greater-sized substrate.
A substrate cleaning apparatus of the present invention is adapted to remove foreign matters on a substrate surface and is provided with a sheet, roll, and rotating unit. The sheet is arranged to be in contact with the substrate surface. The sheet is wound on the roll. The rotating unit rotates the rolls wound with the sheet with respect to the substrate.
The substrate cleaning apparatus of the present invention automatically rotates the sheet by the rotating unit for cleaning the substrate surface. Thus, unlike the conventional manual cleaning, the foreign matters can be removed with less loss time and operation time, efficiency of the removal operation is enhanced, more stable cleaning is provided, and the foreign matters can be reliably removed.
In addition, the rolls enable automatic feeding of the sheet. Thus, cleaning can always be performed with a new portion of sheet, whereby an operation loss would not be caused in feeding the sheet.
In the above described substrate cleaning apparatus, preferably, the sheet is adapted to be brought into line contact with the substrate surface.
The rotation of the sheet in line contact with the substrate surface allows the foreign matters on the substrate surface to be scraped off the substrate surface, and the foreign matters would not be caught between the sheet and substrate.
In the substrate cleaning apparatus, preferably, a sheet supporting member is further provided which is in line contact with the sheet surface opposite the substrate. The sheet supporting member is rotatively supported to incline a portion that is in line contact with the sheet.
The rotation of the sheet supporting member allows the sheet to be rotated closely in line contact with the substrate surface even if the substrate surface is inclined. Thus, the substrate and sheet are reliably and stably kept in contact during rotation, avoiding the problem of precision or undulation of the substrate surface. Further, cleaning efficiency is enhanced, the foreign matters would not be caught between the liquid crystal panel and sheet or drawn over the surface, scratches would not be caused over the substrate surface, and re-adhesion of the foreign matters to the substrate surface is prevented.
In the substrate cleaning apparatus, preferably, a pressure adjusting unit for measuring a pressure applied to press the sheet against the substrate and adjusting the pressure is provided.
Thus, the sheet can be pressed against the substrate surface with an appropriate and stable pressure, whereby cleaning effect is enhanced and cleaning capability is stabilized. In addition, cell gap unevenness over the substrate is prevented.
In the substrate cleaning apparatus, preferably, the substrate is a liquid crystal panel.
As described above, the substrate cleaning apparatus of the present invention is particularly suitable for cleaning the surface of the liquid crystal panel.